Sevelamer carbonate is an orally administrable polymeric amine that acts as phosphate binding polymer for removing phosphate from gastrointestinal tract. It is marketed under the trade name of Renvela in USA. It was developed as a pharmaceutical alternative to Sevelamer hydrochloride. Sevelamer carbonate is an anion exchange resin, with the same polymeric structure as Sevelamer hydrochloride, in which carbonate replaces chloride as the counterion. Sevelamer carbonate is chemically known as poly(allylamine-co-N,N′-diallyl-1,3-diamino-2-hydroxypropane) carbonate salt.
The processes for preparing Sevelamer hydrochloride involving the cross linking reaction of epichlorohydrin with partially neutralized polyallylamine at room temperature are disclosed in U.S. Pat. No. 6,509,013, U.S. Pat. No. 6,083,495, U.S. Pat. No. 5,496,545 and U.S. Pat. No. 5,667,775. The Sevelamer carbonate can be prepared from the Sevelamer hydrochloride by further treatment with suitable carbonate source.
The Indian Patent Application No. 1893/MUM/2006 discloses a process for the preparation of Sevelamer carbonate, wherein Sevelamer hydrochloride is first converted to Sevelamer free base, and this is followed by the treatment with carbonate source.
The US Patent Application No. 20100331516 discloses a process for the preparation of Sevelamer carbonate, wherein the starting reagent allylamine or polyallylamine is first interacted with a suitable carbonate source.
The US Patent Application No. 20120088886 discloses a process for preparation of Sevelamer carbonate which employs the reaction of polyallylamine hydrochloride with epichlorohydrin at the pH of about 10 to about 11.
The International Patent Publication No. WO2011099038 discloses a process for the preparation of a crosslinked poly(allylamine carbonate), wherein first the crosslinked polallylamine free base was prepared by reacting the polyallylamine base with a crosslinking agent; and this was followed by the isolation of crosslinked polyallylamine free base by increasing the pH and further reaction with carbon dioxide to obtain the crosslinked poly(allylamine carbonate).
Besides the availability of different methods for the preparation Sevelamer carbonate in state of the art, there is a need for an improved process for the preparation of Sevelamer carbonate that is economically significant.